Page 1 SINGER CLASSES 620, 625, 626 AND 628 Page 2 Page 3

Page 1 SINGER CLASSES 620, 625, 626 AND 628 Page 2 Page 3
SINGER
CLASSES 620, 625, 626 AND 628
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- Form 20732. A кН TT
Machines 620, 625, 626 and 628 | o тен _Ñ_—]tT-T ©
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SINGER
SERVICE MANUAL
MACHINES or CLASSES
620, 625, 626 AND 628
Instructions appearing in the Service Manual for Machines of Class 600 generally apply to
Machines of Classes 620, 625 and 626. Instructions for Class 603 Machines generally apply to
those of Class 628. This supplement provides instructions which apply only to Class 620, 625,
626 and 628 Machines.
THE SINGER COMPANY
*A Trademark of THE SINGER COMPANY
Printed Im U. S. А,
insert in Form 20732, Swing Needle Service Manual
INDEX
Bobbin Driver
Adjustment......….……....…cosssenrenseraneenamnneenesesesn eme cencnee a eeonoonanareoa e roecana cano cacao emtacaanaocacanarano enano annecanacane
Removal and Replacement.............. eooecenoeoreneactaseaconncanoee cana can econo reorerereenee eeencoracercencaooceonananereecan
Bobbin Push-Button
Removal and Replacement............... eecnsnoconanacaceranenaes success crscenrenseranarasa cnaneueera care a es sasace0
Chainstitch Adjustments. _................ cencareenna conan . O TO
Hinge Assembly..............—..acm..—— . eneaanenocenanos нее. Canne care ce cerenerrencarennance rame rccacsan case
Hook, Rotating
POSITIONING.......…..… .……occrrarenerssancenrenmenesancencenmre ceneeneenaata ee savane ce cac more Lescec sacs sen anr seras caen anna nana ncanee
Removal... een nea anar aa aereas ranrana ear a enaeencecenreceaneaceneca neon ernenenaanenercacarr ene onenra rene entacrcacacarenere
Inspection and Lubrication.—........-.... e=ereeeroreno nene nene encore ro reeno nene renace nene arate sens tons
Needle-Threader Storage and Use...............-...eens0seeraracrcnnan eeeerooea ooo cacacotraana ae ranoocanerenenenees
Selector Systems
Release Mechanism............. meoeeacooneconn anna co runa eme enana nmicanioroeoare care ee vansresramences sennanme mec cecrcnen0e
The Cam Stack...................... e eeeacnanenaceana amara aca acracasecessencersancenne peeaonaaaeaeooncanaaanaan eranaacanana na cncacane nenes
Bignt-Amplitude and Pattern Selector.................e...- enema LELEEEe peocecroseoaprareanacaneen ear ncenannnanae
Needle-Bar Driving Árm................eece=ecereerecereenoarcen coronan nanencacanareneeconeernrerar econ ecrenane crean reaca nace
Tension, Needle Thread
OIE]... STATE ZE XZ EX sande
Removal and Disassembly
Nenacrlas Lr Er Er EE EE EERE hdd ATENEO?
Reassembiy and Teplacement................ meme RD DDR ee
Li |
hroat-P late Pasition 3racket
NING MO Crm Ml Sm meme eee en eee
- * a am WE
Viring GGT GM oo otto tee eee eee nee
PROPERTY OF
THE SINGER COMPANY
This is a private ond confidential communication to and for the use only
of the employees of The Singer Company and its affiliated companies.
Reproduction, sale, distribution, or publication thereof to the public is
forbidden.
Tra
pa ой --
“ets
INSPECTION AND LUBRICATION
CLASS 626 MACHINES
Remove arm top cover by removing the two screws
and lifting cover from machine.
Lay machine on back, loosen screws from the four
Before any extensive inspection is undertaken to
corners of the machine-bed cover, and remove cover
find causes of faulty operation, the machine should
be thoroughly cleaned and lubricated.
Remove lint, fluff, dust or other foreign particles
from the hook, feed dog, and bobbin case.
from underside of machine.
Wipe out any oil or grease accumulated inside
Remove bobbin case and clean in varsol. Open
face plate and clean out lint or waste collected
around needle bar, presser bar, and pressure regulator.
arm-top and bed covers.
Oil machine as indicated below, and on pages
3, 4 and 5 for specific class of machine.
Apply one drop of oil between the casting and
the bobbin push-button release lever.
CLASS 620, 625 and 628 MACHINES
Remove arm top cover by opening stitch chart, re-
moving screw, and sliding top cover toward left and
off the machine.
= TIN [==]
rn AI
+ - == j
° НН ~~ ARM COVER SCREW
BRUSH AND OIL
oll su
OIL CLEAN AND OIL
UT ES
Oil each of the places indicated, and apply Gear
REQUIRES NO LUBRICATION.
Replace arm-top cover and bed cover.
OIL AND LUBRICATE BOTTOM OF MACHINE
——
rf
-.
ARM TOP COVER HINGE ASSEMBLY
CLASS 626 MACHINES: This class of machine, supplied
only for use with the standard com stock, does not require
the access means provided by the hinged top cover. Ас»
cordingly, the following instructions do not apply to Class
626 Machines.
Removal
Remove top cover from machine as “described on
page 3.
Remove the two self-tapping screws on underside of
cover holding bracket to cover.
Remove holding ring from top lid.
Remove stitch indicator chart from lid.
Remove self-tapping screws in lid, disengaging
hinge.
Replacement
Fasten new hinge in lid with self-tapping screws.
Replace stitch indicator in top lid and secure it with
the holding ring.
Replace self-tapping screws through bracket. Do
NOT tighten securely.
Loosen adjustment screws in bracket.
Adjust lid so that it is flush with top cover. (This
is done by raising and lowering the lid on the slots
provided in the bracket while the adjustment screws
are loose, and by adjusting it to the left or right
while the self-tapping screws are loose in the over-
sized holes.)
When lid is correctly fitted, tighten the self-tapping
screws and the adjustment screws in the bracket.
Replace cover and secure it with two cover screws.
STITCH INDICATOR CHART
Co]
В SELF TAPPING SCREWS
—
EST
THE ROTATING HOOK .f0¿(27
VERTICAL GEAR
SET SCREW —
MARK BEVEL
GEARS
RCTATING po
SCCK toa
Removal
CAUTION: Hook-shaft gears and hand-wheel gea
may be removed to facilitate adjustments. DO NOT
DISTURB THE MESH OF ANY OTHER GEAR IN
THIS MACHINE. All other gears are mated and cor-
rectly timed. Replacements should be made only at
the factory.
Remove needle, presser foot, throat plate, bed
slide, bobbin case, feed dog, cushion-spring bracket,
and position finger.
Remove bed cover,
Remove feed-lifting rock-shaft and feed rock-
shaft with pull-off finger as instructed on page 25,
Service Manual for Classes 600 and 603 Machines.
Remove actuating lever and bobbin driver as in-
structed on page 9.
With chalk or crayon, mark the two bevel gears
as illustrated. (Mark one tooth of one gear, and the
corresponding space for that tooth in the other gear.)
This assures proper mesh when replacing.
Loosen set screw in vertical bevel gear, and re-
move gear from hook shaft.
Lift rotating hook assembiy rom machine.
Replacement
Install rotating-hook assembly into machine. Using
the guide marks previously made, mesh vertical bevel
gear with horizontal bevel gear. Turn vertical hook-
shaft until flat side of shaft is under set screw in
bevel gear, and tighten set screw securely.
Replace bobbin driver and actucting lever, as
instructed on page 9.
Insert pull-off finger into machine and replace
feed rock-shaft and feed-lifting rock-shaft as in-
structed on page 25, Service Manual for Classes 600
and 603 Machines
Check and adjust hook as instructed on pages
7 and 8.
Replace all other parts previously instructed for
removal, except in reverse order,
To Time the Hook
Set needle bar at correct height, and time the
needle-bar vibrating mechanism as instructed on
pages 7 and 8, Service Manual for Classes 600 and
603 Machines.
Insert a Size 18 needle up into the needle clamp.
Remove throat plate, bed slide, bobbin case, and
bottom cover. It is not necessary to remove the feed
dog to time the hook.
Adjust machine for straight stitching in center
needle position.
Turn hand wheel over toward operator until lower
timing mark is aligned with lower edge of needle-
bar bushing on UPWARD STROKE of needle bar. At
this position, point of hook should be at center of
needle as illustrated.
To adjust, loosen the two set screws in horizontal
bevel gear. While maintaining position of needle bar,
turn vertical bevel gear at hook-end of shaft until
point of hook is in correct position. Then tighten
the two bevel-gear set screws securely, making cer-
tain that gears are correctly meshed without binding.
CAUTION: Hub of horizontal bevel gear should
not contact face of bushing.
Replace throat plate, slide plate, bobbin case,
and bottom cover.
VERTICAL BEVEL SET
GEAR
x
HOOK POINT
ALIGNED WITH
NEEDLE
SCREWS HCRIIONTAL 3€EV=L
N
GEAR HUB SHOULD
NOT CONTACT FACE
OF BUSHING
To Position Hook to or from Needle
Set needle bar at correct height, and time the
hook as previously instructed.
Turn hand wheel until point of hook is directly
behind needle. When correctly set, the distance be-
tween the needle and hook-point should be approx-
imately 0.004 inch, as illustrated.
HOOK
POINT
N
‚904 INCH: EEDLE
О © A
SETTING: With bobbin push-button in winding
position, remove locator nut by turning in a CLOCK-
WISE direction. Remove bobbin push-button assembly
(see instructions on page 9), and remove locator.
Carefully mark the two bevel gears, as illustrated,
to assure proper meshing of gears when replacing.
Then loosen set screw in vertical hook-shaft bevel-
gear and remove gear from shaft.
Loosen set screw holding the eccentric bushing.
Turn the eccentric bushing while maintaining posi-
tion of hook, until correct distance between needle
and point of hook is attained.
Replace bevel-gear using the previously-made
guide marks to assure correct meshing of gears.
Replace all other parts in reverseorder instructed
for removal. Set winding mechanism as instructed
on page 9.
CAUTION: Check for binding or end play in hook
driving-shaft. For adjustment and removal, see page
24 of Service Manual for 600 and 603 Machines, and
page 6 of this supplement for removal of hook.
PUSH-BUTTON ASSEMBLY
С
MARK BEVEL
LOCATOR NUT
Bobbin Push-Button Assembly
Removal and Replacement
Open slide plate. Place push-button in winding
position. Lay machine on back and remove bed cover
from machine. Remove locator nut from bobbin driver
by turning in a CLOCKWISE direction. Then remove
the two screws fastening the push-button assembly
to the underside of the bed. Slide assembly out as
a complete unit, being careful not to bend the push-
button release lever.
To replace, follow the same directions as for
removal, except in reverse order.
Bobbin Driver
Removal and Replacement
~~ Co r ' 1! =
Coen slide oiare. Remove ‘hroat plate, bocbin
1258, INC lea cover. Jer átiTEN engin seiecror ст о
ri ches ser neh, Inc Turn Mana wneel until ‘зес
ca :s in ¡TS extreme rear sosirion. Yemove ¡ocaror
Aut, push-outton assembly, and locator. Then slide
nobbin driver up, rotate until apron is opposite feed
deg, and lift out of machine.
To replace, install bobbin driver in machine, ro-
tating it until it seats firmly into place. Then replace
locator, push-button assembly, locator nut, throat
niate, and bobbin case.
Adjustment
To adjust the height of the bobbin driver, place
push-button in winding position and loosen adjustable
extension screw at end of lifting bracket. Press up-
ward on bracket until bobbin rises slightly above top
of bobbin case. Then release upward pressure slight-
ly, allowing bobbin to seat correctly into bobbin
case. Without disturbing this setting, tighten ex-
tension screw securely
BOBBIN DRIVER
LOCATOR
PUSH-BUTTON
ASSEMBLY
ADJUSTING
SCREW Se
LOCATOR NUT
NEEDLE-THREAD TENSION ASSEMBLY
STUD CHECK SPRING
2m ——
RELEASING PIN
TENSION DISCS
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VE
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STUD SET CHECK SPRING
SCREW STOP
TAIL OF
RELEASING SPRING THREAD
PIN GUARD
\ ==
Ue
SET SCREW
THREAD GUARD
10
CUP ADAPTOR 8
SPRING INDICATOR STOP
DIAL
Removal and Disassembly
Open face plate, loosen stud set-screw and re-
move entire tension assembly, as illustrated. Loosen
set screw in dial and remove dial. Turn adaptor to
left until it is free from the stud. Remove indicator
stop, spring, cup, and tension releasing-pin. The
check spring, tension discs, and thread guard should
de removed ‘rom ‘Бе stud as a unit.
Raassemolv and Replacement
Replace releasing-pin in stud. Place tension
discs on the thread guard, align coil of check spring
with holes in tension discs and thread guard, and
place assembly on stud with tail of check spring
entering top groove of sprocket on stud. Repiace cup,
spring, indicator stop (with tab at bottom position),
and adaptor. Replace dial, making certain that stop
on inside of dial is in contact with left side of in-
dicator-stop tab when dial is set at zero (0) tension.
Tighten set screw and place entire assembly onto
machine, with check spring resting on the top sur-
face of the check-spring stop.
Adjustments
For adjustments of the needle-thread tension,
check-spring stroke, check-spring tension, and bob-
bin-case latch tension, refer to pages 21 and 22 in
the Service Manual for Classes 600 and 603 Machines.
THROAT-PLATE POSITION BRACKET
Replace throat plate position bracket in reverse
Removal and Replacement
order of its removal, but observe the following:
Remove throat plate, and set throat-plate posi-
tion lever in REGULAR position. Press left end of
position bracket toward underside of machine bed
Stop plate spring should be replaced with the
curved portions of spring under cross-piece
of lever. Remainder of spring should extend
as far as possible, and remove adjusting screw.
Р ' 3 toward left.
Swing left end of bracket away from machine bed
and remove the two throat-plate clamps with brackets, Position bracket must be inserted in grooves
pins, and springs. Set position lever in DARN posi- under machine bed.
tion and remove screws from indicator plate. Lift
indicator plate. stop plate, and step-plate spring Adjusting screw should be turned in flush
from machine bed, and remove position bracket from with bottom of casting while pressing left
underside of machine. end of bracket toward underside of bed.
INDICATOR PLATE
SPRINGS SERES
ÿ
THROAT PLATE = | ere 1 INDICATOR PLATE
ess,
ETN =
BRACKET _—er"2 XT STOP PLATE
NL ZA
ле о | x
THROAT PLATE = Ноя pe LT. TOP PLATE
CTLAMPS =) = ND Он
S
a SPRING
В = ré
= DE
| | > ZN
=
ADJUSTING SCREW = POSITION BRACKET POSITION LEVER
Ne “ZA
NITO NW
ADJUSTING SCREW POSITION BRACKET
11
THE RELEASE MECHANISM
CLASS 628 MACHINES: This class of machine is not pro
vided with a release mechanism, as such. Disengagement
from the stiteh pattern provided by the replaceable cam
used in this machine is accomplished through neutraliza-
tion of the stitch by the Bight Amplitude Selector, as
described on page 19. Accordingly, the following instruc-
tions do not apply to Class 628 Machines.
LEVER
EXTENSION
PLASTIC
SLEEVE
BRACKET SCREW
Lr
TCP SCRE
Removal
Remove top cover,
Remove tension stud.
Remove two screws holding front stop, and selec-
tor mechanism assembly.
Remove the front stop.
Disengage tension-arm spring from selector mech-
anism.
Remove selector mechanism assembly.
Replacement
Replace selector mechanism assembly in the
machine, fastening it in place with the left screw.
Place the front stop on top of the mounting brack-
et, and fasten it with the right screw.
Place tension arm over stud hole, being sure that
the arm is behind the arm plate.
Insert tension stud.
Loosen the left and right screws (which were
tightened previously on selector assembly and front
stop), and set the bracket parallel with the cross
shaft until the right edge of the bracket is approxi-
mately 1,16" to 3/32" from the cast boss for the
cross-snaft bearing.
Then re-tignten screws.
Engage driving spring, being sure that tail of
spring is up when put into place on release lever.
Again, loosen right screw of mounting bracket and
set stop to limit travel of selector arm (This is done
to prevent disengagement of the selector arm and the
tollower, and yet give free movement to the seiector
arm when selecting patterns.)
Replace top cover.
THE RELEASE MECHANISM (Cont'd)
Adjustments
Setting the Release Mechanism
Remove arm top cover.
Be sure stitch pattern selectors are properly en-
gaged. Otherwise, machine will not engage when in
operation. If machine does not engage after selectors
are engaged, the reieasing mechanism requires ad-
justment as follows:
Loosen bracket screw in adiustable bracket and
engage release mechanism by swinging the bracket
to the right by hand until it engages. Tighten screw.
'_scsen screw on adjustable lever and move the
lever Until it makes contact with the olastic sieeves.
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crew se
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ih
rely,
Setting the Loading Cam
The Loading Cam should be pre-set to within
1/32 to 1/16 inch from cross-shaft boss, as shown.
13
BRACKET SCREWS -e=— =
ADJUSTABLE BRACK 7
<
ADJUSTABLE LEVER я RELEASE
A BRACKET
Front Stop and Selector Mechanism Assembiy
REAR RETURN SPRING FRONT RETURN SPRING
LOADING CAM 1/32” ta 1/16"
CAM SELECTOR ARM SHAFT —
FOR 620, 625 AND 628 MACHINES
sum
REAR STOP |
BUSHING (SPLIT) FRONT RETURN SPRING
CAM SELECTOR ARM SHAFT FOR 626 MACHINE
SELECTOR ARM |
ADJUSTABLE LZVER \
= AUS |
Ч IT >
| NL
| ZN = `
N— om “ING
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>; hs: E <TR à
— EMA | BRACKET |
Sa
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No
—
CROSS-SHAFT
Selector Mechanism Assembly
CAM STACK
SPRING STUD
CAM STACK
CLAMPING SCREWS
TOP CAM
TIMING
MARK
14
CLASS 626 MACHINES: This class of machine is designed
for use only with the factory-installed standard com stack,
and is provided only with a Front Cam Selector Arm. Ac-
cordingly, removal and replacement of cams in this ma-
chine should be performed only by authorized serviceman
during regular maintenanca periods, and those instructions
referring to Rear Cam Selector Arm do not apply to Class
626 Machines.
CLASS 628 MACHINES: This class of machine is designed
for use only with one replaceable Fashion Disc stitch-
pattern com during any one sewing operation, and is pro-
vided only with a Front Cam Follower. Accordingly, those
instructions referring toc Cam Stack Removal and Replace-
ment, Adjustments, and Stops do not apply to Class 628
Machines.
Removal and Replacement
Set stitch pattern selector at “A — K'',
Remove arm top cover and removable Fashion
Disc (stitch-pattern cam).
Remove large screw-stud with its spring.
Remove cam stack.
Replace cam stack, meshing worm wheel of cam
stack with worm of arm shaft.
Replace screw-stud with its spring.
Replace Fashion Disc and arm top cover.
Aciustments
Timing the Cam Stack
Remove arm top cover and Fashion Disc, and
large screw-stud with its spring.
Using stitch-pattern selector, bring rear follower
in contact with edge of top cam of cam stack.
Turn hand wheel over toward operator until timing
mark is at point of contact with rear follower, as
shown.
At this setting, the needle bar should be at its
lowest position.
Loosen each of the three clamping screws on top
of cam stack.
While holding needle bar at its lowest position,
manually rotate entire cam stack clockwise until
timing mark reaches point of contact with rear follow-
er, as shown.
Tighten the three clamping screws.
Replace stud with its spring. Tighten stud.
Replace Fashion Disc and arm top cover.
THE CAM STACK (Cont'd)
Removal and Replacement
Remove arm top cover and control panel.
Remove cam stack as previously instructed on
page 14.
Loosen the clamping screw in lower selector arm
by inserting screwdriver through hole in upper arm.
Remove locating screw from plastic cam.
Remove the screw in rear follower arm.
Loosen the rear-stop-bushing set-screw.
Withdraw selector-arm shaft from rear of machine
arm, reieasing front selector-arm and return-spring,
plastic cam, spring, rear selector-arm, and rear se-
lector-arm return-spring.
Remove selector arms from machine.
Remove two followers from index pins.
Replace two followers, and replace selector arms
with cam and return-springs in position, making cer-
tain that hinged brackets fit into slots in followers.
Replace selector-arm shaft through follower arms.
Replace rear follower-arm screw making certain
that it clamps down on flat part of shaft.
Tighten rear-stop-bushing set-screw securely.
Tighten the clamping screw in lower selector-arm.
<enicce zm stack.
Check ant acjust tne release mechanism as in-
Agiustments
Setting the index Pins
Set stitch selectors at “J'' and “RR”.
Remove arm top cover and control panel.
At this setting, top surface of two arm followers
shouid be approximately 1/64 inch below top surface
of cam stack.
NOTE: Position of two arm followers is determined
by neignt of index pins.
Loosen rear index-pin set-screw.
Raise or lower rear index-pin as required, to bring
top surface of rear follower 1/64 inch below top sur-
face of cam stack, then tighten set screw securely.
Loosen front index-pin set-screw at front of ma-
chine arm.
Raise or lower front index-pin as required, then
tighten set screw securely.
15
STOP BUSHING SET SCREW
REAR FOLLOWER ARM SCREW
N omen CAM
— ==
12 — с mean, e,
DÍ
CAM SELECTOR ARM SHAFT >
FOR 620, 625 AND 628 MACHINES
|
77 \
Г REAR INDEX
PIN SET SCREW
E
FRONT INDEX
PIN SET SCREW
CAM STACK (Cont'd.)
=
y O
ZIGZAG
ARM FOLLOWERS CAM
| STOP BUSHING 010
| SET SCREW SET SCREW to
ARM STOP HEX HEAD .010
SCREW SCREW to
| .012 INCH
FRONT
FOLLOWER
REAR
FOLLOWER
Setting Cam-Selector-Arm Stops
Remove arm top cover.
Check adjustment of worm wheel shaft (see in-
struction on page 17).
Set selector at “‘D’’ and “‘L’".
Turn hand wheel over toward operator until arm-
bracket followers rest upon high points of bottom
— (zigzag) cam of cam stack.
16
At this setting, when stitch pattern selectors are
depressed as far as possible, clearance between
both followers and high point of bottom cam should
be 0.010 and 0.012 inch.
Front Selector-Arm Stop
Disengage release mechanism by pushing in on
upper selector button. |
Loosen screw in front selector-arm stop and de-
press top selector button until there is approximately
0.010 inch clearance between front follower and cam.
Maintain this clearance while moving stop toward
front of machine until it makes contact with front
selector-arm. Then tighten screw securely.
Rear Selector Arm Stop
Loosen stop-bushing set-screw at rear of cam-
selector arm-sacrt. 7ress lower selector button until
there is approximarely 0.010 ¡nen clecrance between
-ecr “atiower ana cam.
‘Acintoin mis setrino vniie TMOVING STOD DUSNING
na
7-я
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TWIT sine AT. (т оке CTONTOCT WI
rear “el:Cwer-arm, ‘nen r1gnten ser screw secureiy,
Aligning Indicator with Selector Letters
Indicators ‘‘À’’ to ‘‘j’’
Loosen set screw through hole in upper selector
arm.
Align indicator mark with “A”' position on front
panel, making sure that rear foilower is in contact
with aluminum bignt-control ring (lowest ring with
largest diameter under the cam stack). Tighten set
screw securely.
Indicator “‘K’’ to “*Special’’
Loosen hex head screw in front follower arm.
Align indicator mark with “K'' position on front
panel, making sure that front follower is in contact
with aluminum bight-contr ol ring (third ring from bot-
tom under the cam stack). Then tighten hex head
screw
)
CAM STACK (Cont'd.)
4
Cam-Selector-Arm Shaft Retum-Spring
Removal and Replacement
CLASS 620, 625 and 628 MACHINES:
To remove front selector-arm return-spring, follow
procedure described abave for removal of cam-selec-
tor-arm shaft down to withdrawal of shaft from rear
of machine.
As shaft is withdrawn, the tension-type return-
spring can be lifted from between front and rear disc-
selector-arm brackets.
To replace, insert new return-spring between front
and rear disc-selector-arm brackets, slide shaft for-
ward to engage spring, and reassemble cam-selector-
arm shaft and follower as described.
To remove rear selector-arm return-spring, follow
procedure described above for removal of cam-selec-
tor-arm shaft down to removal of selector arms from
machine. This procedure releases coil-type rear re-
turn-spring.
To replace, fit new return-spring on shaft and
reassemble cam-selector-arm shaft and followers as
zZescribed apove,
Tear ang 26iust the -elecse mechanism as de-
' -
- +
17.520 ON 20G8 >.
CLASS 526 MACHINES
To remove selector-arm return-spring, follow pro-
cedure described above for removal of cam-selector-
arm shaft down to withdrawal of shaft from rear of
machine,
As shaft is withdrawn, the tension-type return
spring can be lifted from the shaft between the legs
of the selector-arm bracket.
To replace, fit new return-spring on shaft and
reassemble - cam-selector-arm shaft and follower as
described above,
Check and adjust the release mechanism as in-
structed on page 14.
17
REAR RETURN SPRING SET SCREW
PLASTIC CAM
ARM BRACKET
REAR RETURN SPRING ARM BRACKETS
A am Ep ER ey ws em A A ey Wm Em ap am
32% ana 523 ‘Aocnines
EE a A a A A RE «== a a
REAR STOP BUSHING (SPLIT)
+ ——— ete оно Нннний, ‘
1 . i |
' —aqm ченнрннчоинний,
`— а
PLASTIC CAM
ARM BRACKET
——
i A
] “> fi
! á в
—
FRONT RETURN SPRING
626 Mochines
BIGHT-AMPLITUDE AND PATTERN SELECTOR
NOTE: The following instructions apply generally to Class
620, 625, 626 and 628 Machines. As indicated on page 13,
however, Class 628 Machines must use the Bight-Amplitude
Selector in lieu of a Release Mechanism in order to neu-
tralize the particular zig-zag stitch pattern provided by
the replaceuble Fashion Disc utilized. Accordingly, the
section on page 20 dealing with Bight-Amplitude Adjust-
ments will be particularly applicable to users of Class
628 Machines.
Removal and Replacement
Remove arm top cover, face plate, and control
panel.
Set stitch-pattern selectors at “A” — *K”,
Remove driving-am spring.
Remove bight-lever screw from bracket, and re-
move bight lever.
Loosen bight-amplitude set-screw and remove.
entire cam stack assembly.
Remove bight-amplitude and pattern selector.
Replace pattern selector in the reverse order of
its removal.
Observe the following:
Assemble cam stack as a complete unit. Upper
eccentric half of worm wheel shaft should be turned
toward hand-wheel-end of machine, as shown.
Make certain that driving-arm ball-pivot is en-
gaged with pattern selector.
Set mesh between worm of arm shaft and worm
wheel of pattern-selector by turning bight-amplitude
shaft clockwise so that there is no binding and a
minimum amount of backlash.
Tighten bight-amplitude set screw.
Replace driving-arm spring
Replace bight lever and fasten with set screw.
Adjust machine as instructed below and on fol-
lowing page.
IRIVING ARM
ECCENTRIC
HALF OF
PATTERN SELECTOR
WORM WHEEL
BIGHT AMPLITUDE
SET SCREW
Adjustments
Setting the Bight-Amplitude Stop-Plates
Set index pins at correct height and time the cam
stack.
CHECK: (At No. 1 Position)
With stitch controls set at “A — L = 3*°, operate
machine af slow speed and, at same time, move stitch
width (bight) lever to No. 1 position. Movement of
driving arm and vibrating bracket should stop at same
time that movement of bight lever stops at No. posi-
tion.
Loosen clamping screw in left stop-piate.
Move bight lever to No. 3 position.
Run machine at moderate speed and move bight
lever toward left, to point where there is no movement
of vibrating bracket or driving arm. DO NOT PASS
THIS POINT.
Maintain this position of bight lever, and move
left stop-plate forward (toward operator) against
hight-amplitude bracket beneath cam stack.
Hold stop-plate at this setting and tighten clamp-
ing screw securely.
А? Mo. 5 Zasition;
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zrten-wistn DiQnT: ever to Ne. 3 cosirion. ‘Aove-
ment of ariving arm and vibrating bracket should stop
at same time that movement of bignt lever stops at
No. 5 position.
Loosen clamping screw in right stop-plate.
Move bight lever to No. 3 position,
Run machine at moderate speed and move bight
lever toward right to point where there is no move-
ment of vibrating bracket or driving arm. DO NOT
PASS THIS POINT.
Maintain this position of bight lever and move
right stop-plate forward (toward operator) against
bight-amplitude bracket beneath cam stack.
Hold stop plate at this setting and tighten clamp-
ing screw securely,
19
LEVER
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Vo E DRIVING ARM
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VIBRATING
BRACKET
NEEDLE-BAR DRIVING ARM
NEEDLE BAR DRIVING ARM
TENSION NEEDLE BAR BALL
ARM DRIVING ARM PIVOT
Removal and Replacement
Remove arm top cover and face plate.
Remove cam-selector-arm shaft as instructed on
poge 15.
Remove needle-bar vibrating bracket.
Lift needle-bar driving arm from machine.
Replace needle-bar driving arm in arm of machine
so that ball pivot rides in socket provided for it in
pattern selector, as shown.
CAUTION: Make certain that tension arm is in cor-
rect position in relation to driving arm,
as shown.
Replace cam-selector-arm shaft as instructed on
page 15.
Replace needle-bar vibrating bracket.
7
LEVER pd BIGHT LEVER
BRACKET CLAMPING SCREW
CENTER LINE
GROOVE Adjustments
| | Centralizing Needle-3ar Driving-Arm
т 3 + = | cet cignt-ampiituge stop-piares as instructed an
EE 410: | zoce 18.
E = Set >ignf ¡ever at No. 3 position.
—— — When bight lever is set at No. 3 position, the
center line of needle-bar driving arm should coincide
with a point midway between selector-arm followers.
Loosen bight-lever clamping-screw.
Push lever bracket toward left as far as possible.
1 2 3 4 5 Align center line groove of bight lever with No. ]
| dy | position, as shown.
7 ] Tighten bight-lever clamping-screw. |
7 Move bight lever as far as possible to the right.
D Center line groove should now be in line with No. 5
position, as shown.
If center line groove of bight lever is not in line
with No. 5 position, loosen bight-lever screw and,
while holding bracket to extreme right, move lever
1/2 the distance that it is out of line. Then tighten
bight-lever clamping-screw. Lever will now be an
—^
N
Ww
+
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equal distance from center position No. 3 when set |
at No. 1 and No. 5 positions. —~
Replace arm top cover and face plate.
20
TROUBLE-SHOOTING GUIDE
Chainstitch Adjustments
If sewing defects are encountered in chainstitch-
ing, the procedure given below should be followed
in adjusting the machine. After each step, check
the chainstitching operation. If the machine sews
satisfactorily, no further adjustment is needed; if
the machine does not chainstitch properly, proceed
ta the next step.
Machine Settings
„т
у
Check the machine to be sure it has been set a \
for chainstitching in accordance with the instruction == Case ts
book: use 50 mercerized cotton or “A” silk thread, \
size 14 needle, between 8 and 12 stitches per inch. 3/32" LOOP RETAINER BAR
Check chainstitch performance.
Chainstitch Throat Plate
Check loop-retainer bar for free action; i. e., the
bar should move front to back with no binds. In the
front position, the bar should extend approximately
3/32 inch beyond the edge of the throat plate.
Check chainstitch performance.
When the bar is depressed against the throat plate,
there should be visible clearance (approximately
0.010 inch) under *he rivet head. The bar should also
soring 2acx into position wnen ‘he pressure is re-
PIERCED RIVET HEAD
TAB
— y
‘eased. Check chainstitcn pertormence.
—_— |
| ———— 4
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Machine Agjustments
Check the radial setting of the bobbin case as
instructed on pages 15 and 16, Service Manual for
Class 600 and 603 Machines. The setting should be
to the center, or to the right hand side of the needle.
If radial setting is to the center of the needle, move
it slightly to the right hand side. Check chainstitch
performance.
Gently raise or lower the pull-off finger, by form-
ing up or down until the finger is as close to the top
of the hook as possible but still maintaining thread
space. Check chainstitch performance.
CAUTION: Do not burr or nick the thread-handling
edges of the pull-off finger during forming. BOBBIN CASE
Check for thread clearance in a 12-stitch-
per-inch setting by rotating machine by ECCENTRIC STUD SET SCREW
hand. НН thread clearance is sufficient,
perform normal stitching test.
21
TROUBL E-SHOOTING GUIDE (Cont'd.)
FEED-LIFTING-ROCK
SHAFT ECCENTRIC
PULL-OFF FINGER
HINGE-SCREW NUT
FEED-ROCK
SHAFT ECCENTRIC
NEE
DLE К PULL-OFF FINGER
ory |
| Г PROTECTED
POINT
=p =
22
Remove bottom cover and check that the feed-lift
and feed-rock-throw eccentrics. are correctly assem-
bled in the machine.
(Lay the machine on its back, panel facing up-
wards. Rotate the hand wheel until needle is at its
lowest point. The hook point will be near the posi-
tion finger at the lowest point. In this position, both
throws should be down. If the throws are not down,
reposition as described on pages 13 and 14 of Service
Manual for Class 600 and 603 Machines.)
Check chainstitch performance.
With the bottom cover removed, install a No. 18
needle, and rotate the hand wheel until the needle
bar is at its lowest position, then continue to rotate
until the hook point is directly behind the needle.
Loosen the pull-off finger hinge-screw nut and the
hinge-screw, allowing the pull-off finger to move
freely. Allow the pull-off finger to rest lightly on the
needle; then, holding the nut in position, tighten the
screw.
CAUTICN: Raise ana lower the needle sar >y ro-
*ating the nand wnee: forward and sack to
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‘ne neecie, cousinc .7 TO Iefiec? icains:
the nook point. Mola the screw tignt and
draw up the lock nut. Repeat the precau-
tionary check above, to be sure the pull-
off finger does not deflect the needle. Re-
place bottom cover.
Check chainstitch performance.
Trademark Medallion
The trademark medailion on the uprignt arm can
be removed easily in order to gain access to the
panel and screws. Gently pry the medallion from the
arm with a protected screw-driver point or other long,
slender instrument.
To replace, position stud over hole and gently
ease medallion back into position.
u
TROUBLE-SHOOTING GUIDE (Cont’d.)
Needle-Threader Storage and Use
(Class 620 Machines Only)
Servicemen should be aware of common customer
mistakes in the handling, use, and storage of the
Needle-Threader attachment. The following instruc-
tions cover the procedure suggested to users of new
Class 620 Machines, and reflect the most common
causes of damage and misalignment. As such, they
can be of use for trouble-shooting during service
calls.
To prevent damage to and ensure proper alignment
of the Needle-Threader attachment, the procedure
given below should be followed in storing and using
this device.
1. When not in use, the needle-threader should be
stored in the space provided behind the face plate.
2. Before using needle-threader, be sure that presser
foot is lowered, and remains lowered while needle-
threader is in use.
CAUTICN: DO NOT raise presser foot while needle-
*hrecder is attached to needle.
3
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4. Attach supperting arm to lower-thread-guide clamp-
ing-screw through larger end of machined hole in
arm. Upper and lower guides and needle-threader
hook should now be aligned with needle eye.
tn
. Using gripper-piate on supporting arm, gently pull
arm forward until nook passes through needle eye,
and guides engage needle shaft. The needle-thread-
er is now ready for use.
6. To remove needle-threader from needle, pusn back
gently on gr -per plate, free thread from hook,
disengage supporting arm from lower-thread-guide
clamping-screw, and carefully swingneedle-thread-
er assembly back up to storage nest.
CAUTION: DO NOT close face plate while needle-
threader is not properly stored.
——i
—— NEEDLE
THREADER
LOWER THREAD GUIDE ©
CLAMPING SCREW TONI PRESSER FOOT
. \\' | С коневео
=
+ . =
CLAMPING SCREW
ATTACH THREAD GENTLY PULL-THREAD
TO HOOK THROUGH NEEDLE EYE
23
TROUBLE SHOOTING GUIDE (Cont’d.)
Lo
Needle-Threoder Removal and Replacement
Remove pivot-pin-screw and spring from base of
needle-threader supporting arm.
Remove needle-threader assembly. Set pivot-pin-
screw and spring aside.
Replace needle-threader assembly by positioning
it over machined hole. Be sure that threading hook
is pointing up.
Replace spring with larger end against supporting-
arm.
Replace screw and tighten securely.
Needle-Threading Hook Removal and Replacement
To remove, lower needle-threader.
Remove screw from threader arm, as shown.
Push damaged hook out through threader arm.
To replace, insert new hook (thread slot up) from
the rear of the needle-threader through the space
between the threader arm and guide.
‘Align the holes in the hook body, needle guide,
and threader arm. Replace screw.
Lower the oresser foot and raise the needle bar
to its nignest position.
Position slot in “hreacer arm over positioning
om
= has
2w эп лееа!е с:стр.
NOTES:
24
— WIRING DIAGRAM
CARRYING CASE ADAPTER
OFF-ON SWITCH (WIRING SIDE)
LIGHT SOCKET CONTROLS POWER TO
WITH LEADS LIGHT AND MOTOR
N. =
MACHINE PLUG
FRONT OF
on
ON-OFF SWITCH TT |
PA 9-8 MOTOR
MOTOR
= < >= MACHINE RECEPTACLE
MOTOR —_— ; |
— HP
/ LINE PLUG
FOOT CONTROLLER
25
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